Are you in the USA? If so she has no legal right to enter your house uninvited unless someone has a warrant to enter. I would stop that right now. Let her sit in the parking lot all she wants but don't let her in. She will probably get mad and may even threaten to take action against you but tell her to bring it on. I would be damned if someone would tell me I could not have a gun unless I was a threat to harm me or someone else.

Talk to her supervisor and say this stops now.